Question

Let u be the universal set containing 700 elements. If A, B are sub-sets of such that n (A) = 200, n (B) = 300 and n(A⋂B) = 100.Then, n(A'⋂B') = 

A. 400 

B. 600 

C. 300 

D. none of these

Answer 1

Here, 

n(A) = 200 , n(B)=300 , n(A⋂B) =100,n(U) =700 

n(A⋃B) = n(A) + n(B) - n(A⋂B) 

= 200 +300 -100 

= 400 

n(A'⋂B' ) = n(U)∖n(A⋃B) 

= 700 - 400 

= 300